Fancherized Twister Questions

I am about to embark on building a pair of Fancherized Twisters from plans obtained from out host. Before proceeding beyond the rib cutting stage, I would appreciate any help that you might give me in two specific areas.
First, the plans show an LA 25 for the power plant. I know that a well prepared 25 - - such as the TT 25 GP that Leonard prepared for me several years ago - - has a lot of grunt and rivals that of my tricked-out Fox 35. However, the Twisters that I have observed have been flown, for the most part, on OS 40 FPs. Have any of you flown Twisters with the equivalent of an LA 25? How was the performance? Would you recommend that size engine (assuming, of course, that I succeed in keeping the planes light)? What do you think is the ideal engine for a lightly built Twister?
Second, I am paying more attention than I ever have to wood density, a carry over from a couple of years of building Penny Planes, MiniStiks, and EZBs. What density wood should be used for the 1/2" plank fuselage (which will be covered with at least silkspan and maybe 1/2 oz carbon mat)? Would 6 - 8 pound wood be about right? What about the 1/2 x 1/2 leading edges?
Thanks you for any advice you might share with me and the rest of the gang.

I first flew my Fancherized Twister with an OS FP 25. It flew just fine even though it was on the portly side at about 46 oz at the time.

My problem was I found it difficult to build the long fuse version light enough in the tail to balance without nose weight. The first experiments needed 4 oz in the nose!!!!

I re-built the elevator and joiner removing over an oz and put in an FP40.

It also kind of depends upon what you expect the plane to do for you and what level of experience flying you have. I found the "comfort" of having alot of power available to be nice as a raw beginner--but I could fly that plane with a 25 in it now with no trouble at all.

As to the fuse, I would heed the notion of keeping the fuse stiff. If you use 4-6lb wood, apply 1/2-3/4 oz glass over the fuse al la Cardinal Profile. Or build in some stiffening.

Look at Larry Cunninghams excellent series of articles on building profiles--on the PAMPA website. His builtup fuse construction is very stiff and light enough.

I think everything else on the plane, including the LE should be as light as you can find--if you use the 1/2 sq LE. You might get some slightly harder wood if you make a built-up LE per Tom Morris. I like to use straight spruce as the Morris Lincoln Log "core" for the LE. But that isnt really necessary.

Also, the above are predicated on a doped silkspan wing--if you use heat shrink covering, you might want to use stiffer wood in the maain structure.

Remember, whatevery you do, and however heavy you make the wing to "make it crash resistant" it is going to come apart in a serious crash anyway. Build it as light you can and take every effort to keep it straight. Its amazing how well these will fly.

FWIW

Engine, depends on what you intend to do with the Twister. If you are building it for fun fly and keep it light the 25 will be fine. If you are planning on campaigning it on the contest circuit I would recommend a Brodak 40 or Saito 40 FS. The larger engine will broaden the range of needle settings and weather conditions you can fly a good pattern in.

For example lets say you get off on an official flight with the needle just a tad rich and the wind is blowing 10 - 15 MPH. Not unusual at any given contest. The 25 may or may not have the poop to get you through the flight and even if you get through the flight it won't be the best you and the plane are capable of. The larger engine will have the reserve power to make up for the slightly rich setting and just fly the pattern.

I would use a little harder wood on the leading edge and laminate it from two pieces of 1/2 x 1/4. Use slow drying CA to do the lamination, Titebond will warp the wood. You can end up with a dead straight leading edge this way and it will be stronger than one piece of wood.

My TwistMaster has a fuselage made from 1/2 inch 6 lb contest balsa and except for the fingernail marks from people holding it it has held up fine. I routed a 1/4 inch slot from just under the wing to the aft end of the fuselage and glued in a piece of 1/2 x 1/4 spruce. This stiffened up the back end enough to prevent the tail from waggling. If I had covered it with .2 oz CF I probably wouldn't have the fingernail problem and may not have needed the spruce. BTW: I am positive the tail doesn't waggle because I have the video

My stock Twister flies fine with an OS 25fp. I run it screamingly lean with a low pitch prop. Does a decent pattern. If I built another I'd use thinner nose doublers. Keep the stock ones if you're using a Fox 35.

When I first learned to fly inverted (that means being able to fly more than two laps without smacking the tar) a stronger engine was very helpful.

Since I was prone to get scared and screw up at any moment I was preacticing with more power, so that I colud bail out to normal flight at any part of the circle.

That means that if I got the heebie jeebies on the upwind side of the circle I could just give a "down" (the upper part of the hande forward) and get back to normal flight without loosing tension.

Same applies to learning most maneuvers. With some more engine you are less prone to loose tension due to wromg placing on a horizontal eight than with a more "artistic" (slower) engine run.

God bless you!

In Christ,

Thank you Curt, Bob, Jerry, and Ion for your very helpful comments and suggestions.
As for power, I am persuaded by your comments that I should use my 40FP or, depending on how the planes balance, my (heavy) Brodak/K&B 40. Since I use what Larry Cunningham calls the New Mexico Universal Engine Mounting Plates (as shown on the Mo' Best plans) switching motors is very easy.
I will cover the fuselage with either .5 oz glass or .2 oz carbon mat. I learned the need for that when building my Magician (Golden State kit) with a fully-tapered fuse aft of the trailing edge. Without the .5 oz glass applied with finishing resin I am sure the fuse would have snapped in the first hard corner.
Larry Cunningham's articles on building a better profile are terrific and I like the built-up profile fuselages. I used them for a trio of re-engineered Skyrays which, due in no small part to the lightness of the fuselages, weigh just 18 oz (with single peg gear, silkspan and just clear on most of the wings, but w/o motor and tank). However, for my first couple of F'Twisters I am going to stick to the 1/2 in plank (6#, thank you, Bob).
I want to use light weight transparent Ultracoat on the wings. I am going to try the film-over-silkspan method recently described by John Miller on this forum. That should provide adequate torsional rigidity without having to resort too heavier lumber.
Thanks, again all. I had better get on with my rib cutting.

LAST EDITED ON Nov-08-03 AT 11:46 AM (CST)
 
Just one comment on the fuse. If you use a low vibration engine, you might get away with using light wood. Your reinforcing it with the fiberglass is also a good idea. On my Twister (which I "Fancherized"), the stock fuse blank was actually pretty light--as was the wood I used for the extension. I noticed that the tail end moved sideways quite easily---and I had applied silk to the fuse. So see if there are any other opinions about using such light wood for a fuse profile.

I really like the fancherized Twisters made by Bob Hazle. Jim Renkar bought one of them and it is really sharp. Jim is now running it with an OS35s, although it originally had the 25FP (or was it a 20FP?)

As I mentioned in another thread, my Twister is now in pieces--a casulty of learning (well, trying to learn ) the full pattern. Twisters are pretty common around here (Midwest) and considered to be pretty darn good planes. When I make my next one I plan to do one of Tom Morris's Millineum wings. I just don't like the 1/2 square leading edge. I never seem to be able to find pieces like that which are straight. They are such big hunks of wood compared to the rest of the standard wing structure, I always end up with a warp.

The only suggestions I would add are I use 1/4" 48in long spruce for
spars, and half ribs to keep the covering from sagging to much.
I forgot I also use 1" balsa for the wing tips

LAST EDITED ON Nov-10-03 AT 06:20 AM (CST)
 
>most part, on OS 40 FPs. Have any of you flown Twisters
>with the equivalent of an LA 25? How was the performance?
>Would you recommend that size engine (assuming, of course,
>that I succeed in keeping the planes light)? What do you
>think is the ideal engine for a lightly built Twister?
>Second, I am paying more attention than I ever have to wood
>density, a carry over from a couple of years of building
>Penny Planes, MiniStiks, and EZBs. What density wood should
>be used for the 1/2" plank fuselage (which will be covered
>with at least silkspan and maybe 1/2 oz carbon mat)? Would
>6 - 8 pound wood be about right? What about the 1/2 x 1/2
>leading edges?
>Thanks you for any advice you might share with me and the
>rest of the gang.

Pete;

I've fooled around with a couple of Fancher Twisters over the past year, and have build a number of Twisters over the past 18 years or so. In the past, I have used the Twister wing as a basis for a number of designs. Liked it enough to formalize a set of plans and commit it to CAD. Here are some thoughts and observations.

The Fancher Twister plans were drawn up for those who would like to modify an existing kit. Yes, you can scratch build, but if you decide to do that, then I suggest considering what it is you want to accomplish before building. From my correspondance with Ted Fancher while drawing up the plans and from reading his old articles from MA, the FT was an experiment to see if a ship like the Sig Twister could be made more competitive. Ted proved it could, but like everything it is a compromise. Remember, when he did the conversion the Twister was one of the few capable CL profile kits on the market. That has changed considerably in the past five years.

For the wing, I prefer a C-Tube or something a little more resistant to twisting, especially if you are going to use film covering. I used to chuckle about a couple of Twisters I built in the mid 1980s and covered with Monocoat - the name "Twister" came from the way the wing twisted and flexed. This flexing is not apparent when covered with silkspan and not a problem with that type of finish. Yes, I know that lots have been flown with stock wings and film coverings, but I don't think it is conducive to long life. I have also built one with diagonal ribs to mitigate flexing even more. Makes for a very rigid wing. If you are interested in building the Twister wing from scratch and want to go with C-Tube, let me know and I will send you the CAD extract of the rib.

For the size of the ship and the thickness of the wing, there is a gap as to what is the right mill to put in the nose. Some people think the LA 25 is too little engine. Might be, but I have not found that to be the case. The FP 40 seems to have more to offer than what the wing can deliver. If I was going to scratch build and use an FP 40, I might thicken the wing from 1 7/8" to 2.00 or 2 1/8". Thus far, my favorite engine for this wing in a profile is the Max-H 40 set up for control line. With an 11-5 and 10% nitro, it is a happy combination. I think the Brodak 40 would also be a good match.

My latest version of the FT utilizes an adaptation of Al Rabe's "BBQB" control setup. Between the top and bottom spar I have a central core of two pieces of 1/8" balsa that are a total of 3" long. The bellcrank is supported on a piece of 1/8" music wire that is the same length as the distance between the two spars. The 1/8" pieces of balsa are relived enough to allow the bellcrank to turn smoothly. Washers are used to center the bellcrank. On both sides of this are placed two pieces 1/16" balsa 3" long, again the same height as the inner distance between the two spars. This whole assembly is slid between to two spars. Note that the assembly is now 1/4" wide - same width as the spars. Then, two pices of 1/32 plywood 3" long are cut out. The height of these is to the top of the spars. They are relieved and then glued to the spars, and hold the bellcrank plate in place. Very light and very strong. I have a detail of this on the new plans and can send it to you if you would like.

I gave up trying to get 3/16" balsa flaps and elevators to work. Go with 1/4". I use polycrylic with silkspan over the control surfaces - no problems. Makes the control very rigid. Also does wonders for the fusealge.

Tom Morris can make a 3.5" bellcrank and pushrod setup for this ship. They are a work of art.

The way Ted designed the nose and the extra wood there to dampen vibration makes for a nose heavy ship. Lengthening the fuse helped considerably getting balance back in check.

Please, keep me informed as you build the FT and any discrepencies with the plans you come across.

Bob:
I bought my plans for the FT from Leonard just a few weeks ago. I want to congratulate you for a beautiful plan. In the course of cutting up a copy for templates I have done a lot of measuring and comparing - - e.g., comparing the wing cut-out on the fuselage with the rib template - - and I have so far found no discrepancies. I doubt that I will.
Your comments and suggestions about the FT are simply terrific. I very much appreciate them as, I am sure, will anyone interested in the FT.
My FTs will be used to develop my flying skills beyond the horizontal eights, something of a plateau on which I seem to be stuck. (The fact that I fly very little no doubt has something to do with that.) For the foreseeable future, the FT as shown on the plan will be much more capable than its pilot. Therefore, not all of your suggestions will be incorporated in the first one or two that I build. Your suggestions, however, will help me improve the plane as my flying skills improve.
In your comments you said: "For the size of the ship and the thickness of the wing, there is a gap as to what the right mill is to put in the nose." As a way to help fill that gap you suggested that the thickness of the airfoil could be increased. As a substitute for increasing the airfoil thickness, what would you think about simply adding one bay to each wing panel to increase the span to 53 1/2 in. and the area to about 540 sq. in.?
Thank you for taking the time to share your experience with us.

> Have any of you flown Twisters
>with the equivalent of an LA 25? How was the performance?

I've flown several with 25FP's and they are the equal of almost any "full-house" stunt plane. A stock 25FP is preferable, in my experience, to a modified 40, since all the 25FP models flew tremendously better than the modified 40 models. And a stock 40FP is too powerful and will be very difficult to control. With the 25, you really don't need to worry too much about weight. 36-38 oz is light enough.

As far as the LA goes, I'm less sure. My understanding is that they have reduced power due to the lack of the boost port, and thisallows them to "lug" better, but not use as good a prop.

Recall that Bob Smiley has been flying his Mathis Excalibur with a variety of engines, the last (and best, he sez) being the .25LA. As the Excalibur is bigger than the Twister, and in the same or higher weight range, it would seem the .25LA would be just fine. Steve

In addition to adding the half ribs, I webbed the center sections between the spars as well as the trailing edge. Webbing the trailing edge stiffened the uncovered wing enormously. No twist-her now.

I used cy for the webbing to reduce warps. Looks straight.

>
> I've flown several with 25FP's and they are the equal of
>almost any "full-house" stunt plane. A stock 25FP is
>preferable, in my experience, to a modified 40, since all
>the 25FP models flew tremendously better than the modified

Brett;

What prop setup have you used with the unmodified FP25 that you felt did a good job?

Agreeing with Jerry, I like a Y & O (original, not the more recent one) 10-4 on my SSW-erized FP 25, but set in a Wet Two, not screamingly, Kenyan marathonerish lean.

>
>>
>> I've flown several with 25FP's and they are the equal of
>>almost any "full-house" stunt plane. A stock 25FP is
>>preferable, in my experience, to a modified 40, since all
>>the 25FP models flew tremendously better than the modified
>
>Brett;
>
>What prop setup have you used with the unmodified FP25 that
>you felt did a good job?
>

9-4 APC, 10-4 APC, or 10-4 Rev-Up.

Last August I flew my first stunt contest since 1968, with a loaned Twister. It's a long story, but put me down as an admirer of the Twister. I was amazed (favourably) at the ability of the model. It has meant that I rally should build one for myself, and a Fanched one as well, but so much to do...

Send the plans to Russia and get a boatload of them ARF'd. Steve

I have an OSLA40 on a Twister. Tail 3 inches longer, stock tail half ribs. Else all is standard. Very stable flies quite well and great balance. It presents quite well in the air and is capable of 500 point flights. Fox 35 is too light. Also flew quite well with the rustler merco 40.

I have an OSLA25 on a 38 oz primary force. works well but I would be hesitant to put it on this twister. You need more umph from a larger diameter prop to get a contest performance.

Bob Smiley
A Lancair 360 builder/flyer trying to be a modeler

>I have an OSLA25 on a 38 oz primary force. works well but I
>would be hesitant to put it on this twister.

I'm glad you said something. I was thinking of your 25LA models when I was hesitant to recommend them on the Twister. It did not seem to be up to the task on the Primary Force.

I do know for certain that a 25FP will fly the heck out of a Twister. But the LA seems to come up a bit short.

LAST EDITED ON Nov-13-03 AT 12:27 PM (CST)
 
Anyone flown a Twister with a ThunderTiger Pro .25 (Dual Ball Bearing and tru venturi)? Would it be good on a Twister with a 9.75-3.7 Eather 3blade? Inquiring minds again!

Thanks

I really like my TT 36 pro's--I suspect the 25 would be just as smooth and similar to a FP25 in power. Havent actually run the tt25 but If it is similar to the OS--not real reason to think it would be too far off---the three blade might be a bit too much prop for it.

In any case, the engine would well on the twister I think, as long as it wasn't too heavy.

Lots of speculation here but it sounds like a promising experiment.

Let us know.

Now if you have Leonard do up one, it would most definitely provide the required poop--probably even for that prop or more.

>Anyone flown a Twister with a ThunderTiger Pro .25 (Dual
>Ball Bearing and tru venturi)? Would it be good on a
>Twister with a 9.75-3.7 Eather 3blade? Inquiring minds
>again!
>

Jim;

Yes, I have, but I modified it by blocking the boost port and the addition of one head gasket. So far I have run it with a 10.5-5 two blade with good success.

The Magnum BB 25s and the OS BB 25s also seem to work well with a similar setup.

Don't know about the Eather 3 blade. I'll bet there is only one way to find out.